Multiphase equipment protection



Nov. 20, 1928.

A. N. ORR ET AL MULTIPHASE EQUIPMENT PROTECTION 2 Sheets-Sheet 1 Original Filed March L7, 1 22 [7 Men tars: Angus N Orr.

59/0010" Ga/Jk/Z Nov. 20, 1928. A NORR ETAL 1,692,138

HULTIPHASE EQUIPMENT PROTECTION Original Filed March 17. 2 Sheets-Sheet 2 u /uo Sa/aman add/berg Patented Nov. 20, 1928.-

UNITED STATES v 1,692,138 PATENT OFFICE.

ANGUS 0BR AND SOLOMON H. GOLDBERG, OF CHICAGO, ILLINOIS.

MULTIPHASE EQUIPMENT PROTECTION.

Application tiled March 17, 1928,. Serial No. 544,485. Renewed June 2, 1928.

This invention relates to improvements in electrical fuses and a method of connecting the same in power lines to protect equipment operated by multiphase current, and refers more particularly to fuses which may be so connected in power lines that if the fuse in one line is blown the fuses-in the remaining phase lines are also blown, thereby disconnecting the power source from the system.

Among the salient objects of the invention are to provide fuses which are particularly adapted to be connected .up in power lines serving as connections between generators and motors, the fuses being so connected that the motor or other equipment cannot be operated on any but the required number of phases. a

Fig. 1 is a dia rammatic showing of a three phase motor an generator hook-up with the I fuses inserted in the separate phaseline.

Fig. 2 is a cylinder system showing a modified form of fuse being used in the lines.

Referring to the details of the drawings, at 1 is shown a motor generator which supplies current to operate the motor 2. The current is suppliedthroughthreeseparatephasesorlines designated as 3, 4: and 5. At 6 is interposed a knife switch which may be thrown out when the power is to be cut off. To follow the course of the initial phase, follow the line 3 through the knife switch and into the bottom of the cylindrical fuse 7. The three fuses, 7 8 and 9 are identical in structure, having alower metallic ca 10, a fiber cylindricalbody portion 11 an atop metallic cap 12, Two side connections or b nding posts are positioned in the body portion at 13 and 14. A lowercontacting spring 15 is soldered or otherwise fastened to the lower metallic cap and makes a connection therethrough with the wire 3 and an upper contacting spring 16 attached to the upper cap and likewise makes a contact therewith. The two'springs are fastened to the bindin post 14 by means of a fusible substance suci as lead shown at 17. Similar metal is interposed between the two springs asshown at 18.1 The particular type of construction of the fuses may vary in numerous details without departing from the sco e of the invention, as the particular method 0 connectingthe springs with the caps and the binding 90st connections inthe side of the body of the use offer innumerable opportunites for variation. The current supplied through the line 3 proceeds through the spring 15 and thence on through the spring 16 and out through the upper wire connection 3 to the motor 2. A second phase supplied from the generator flows through the intermediate wire 4 and through the middle fuse 8 in an identical manner that explained in 7 and out through the upper connecting line 4 to the motor 2. The third phase supplied from the generator through the wire 5 proceeds through the knife switch (3 and fuse 9 to the motor 2 through the upper connecting line 5.

If for some reason or other the load upon the separate lines becomes unbalanced or an "excess load is thrown upon the line 5, the fuse a connection through the resistance wire 19 and causes the fusing of the lead which holds the contacting springs in the fuse 8. With the releasing of the lower spring 15 in the fuse 8 this will snap over into a position shown by the spring in the fuse 9 and contact with the projecting portion of the binding post 13 in the body portion of the fuse 8 which in turn will short circuit the fuse 7 in the same manner, thereby cutting off the entire current of the-generator from the motor. a

It is obvious, of course, that the blowing of the fuses is practically simultaneous so that immediately with the blowing of one'fuse the entire current is cut off from the motor-.-

At the present time with the common type of fuse it is often possible and a common happening for one fuse to blow out and the motor hum along on two phases. It is not long under operation of this sort before the motor is completely burnt out and must be rewound before it can be again satisfactorily used.

Where a. motor is not constantly'attended and carefully watched, it is extremely desirable to have some means of cutting the current or notifying an operator in case one of the lines becomes shorted'or disconnected, as it takes a very short period of time to ruin a motor when operating on anything less than the In Fig. 2 a similar type of construction is.

shown, the power being-supplied from the generator and thecurrent passing through the separate lines 21, 22 and 23 in which are interposed the fuses 24, 25 and 26. The construction of the fuses is somewhat different from those shown in Fig. l as there is positioned in the body of the fuse a plunger 27 which is attached to the lower cap by means 1 of atension spring 28. The plunger is raised to thetop cap and there fastened by means of fusible metal. such as lead shownat 29. If

. conditions in the line 23 are such as to cause the fusing and blowing of the fuse 27, the metal 29 holdin plunger 27 to the to cap of r the fuse, will re ease the plunger an permit the tension. spring'to take effect thus-drawing the plunger. downwardly. Normally, the lower cap of the fuse is connected through theplunger and fuse metal with the upper cap y'means of a flexible wire 30. As the plunger is drawn down by the tension spring, a plug-31 held in place against the'side of the body portion-of the fuse by a compression spring 32,- contacts the binding post 33 in the side of the body portion as shown by the fuse 25 in Fig. 2. -At this time the current through the line 23 is short circuited into the fuse 25,

fusing the metal which holds the plunger in the fuse 25 and causing that plunger to be drawn down by a similar tension spring in that fuse. In the same manner the contact ing plug will short circuit the fuse 24 and' has been blown. The operation of this sys-.

tem is identical to that shown in Fig. 1, the difference lying only in the details construction of the individual fuses. a

fuse 25 and has blown. that fuse.

The functioningpf the system is complete and satisfactory and its utility'is readily appreciated when-the blowing of three inex-' pensive fuses will prevent the burning out of the motor, an accident which requires the complete rewinding and substantial expense.

We claim as our invention: 1. Electric fuses for multiphase equipment, consisting in fuses with line connections adapted to interposed in the separate phase lines, springmeans in each fuse and a fusible I substance uniting the connections and said spring means and holding a spring tension upon the latter, contacting means in each fuse and connections withsthefuses in the other lines, whereby with the blowing of one fuse the connected lines are short circuited and the fusesblown. V v

- 2. Electric fuses for multiphase equipment, consisting in fuses with line connections adapted to be interposed in the separate phase lines, spring means in each fuse and a fusible substance uniting the connections and said spring means and holding a spring tension upon the latter, contacting means in each fuse and connections with the fuses in the other lines, whereb the releasing of the spring means in one use with the blowingthereof, is adapted to function through the contacting means and connections to successively short circuit the other phase lines. I x

3. Enclosed electric fuses for use in series in multiphase systems, each fuse comprising a hollow shell closed by caps, promoting springs attached to the caps bent lntermediate their length to contact and be fused with an electric connection inserted in the wall of the shell, an a rture on the wall of the shell opposite the oregoin 'v electric connection for inserting another efectric connection with which latter one of the springs contacts'when in normal position after the fuse has blown, to transmit current through said electric connection, to the succeeding fuse or fuses in the series. a 1

- ANGUS N. ORR. i SOLOMON H. GOLDBERG. 

